How 'Angel's Glow' Saved Civil War Soldiers—and Baffled Scientists for 140 Years

For over a century, the strange glow seen in the wounds of soldiers after the Battle of Shiloh remained unexplained. Known as 'Angel’s Glow,' this eerie phenomenon puzzled historians and scientists alike. The mystery was finally solved in 2001 by two high school students, Bill Martin and Jon Curtis. The Battle of Shiloh in 1862 was one of the bloodiest conflicts of the American Civil War. Over two days, 23,746 soldiers died, and 16,420 were wounded. Many survivors reported that their wounds emitted a faint, blue-green light at night, which they called 'Angel’s Glow.' Surprisingly, those with glowing wounds often recovered better than others.

In 2001, Bill Martin and Jon Curtis investigated the phenomenon for a school project. They discovered that the glow came from *Photorhabdus luminescens*, a bioluminescent bacterium. This bacteria lives in soil nematodes and produces toxins that kill harmful microbes. While it cannot survive at normal human body temperature, the chilly conditions of the battlefield allowed it to thrive. The bacteria’s light is created by the *lux operon*, a group of genes that trigger bioluminescence. Beyond glowing, the bacteria also disinfected wounds, reducing infections and improving survival rates. Martin and Curtis’s findings won first place at the 2011 Intel International Science and Engineering Fair. Their work was later featured in a Smithsonian Magazine special report on the Civil War.

The discovery of Photorhabdus luminescens explained a long-standing historical mystery. The bacteria’s glow not only fascinated observers but also played a role in saving lives. Today, the story of 'Angel’s Glow' serves as a remarkable example of how science can uncover hidden truths from the past.